<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <style>
    div {

      /* overflow: hidden; */
      width: 100%;
      height: 1100px;
    }

    iframe {

      width: 100%;
      height: 100%;
    }
  </style>
</head>

<body>

  <a href="/index.html" target="fm">dads</a>
  <a href="/login.html" target="fm">xxxxx</a>


  <div>
    <!-- 实现页面切换效果 -->
    <iframe src="" name="fm" frameborder="0"></iframe>
  </div>

</body>

</html>